Altitude switch



Dec. 11, 1956 G. J. DAVIS ALTITUDE SWITCH 2 Sheets-Sheet 1 Filed March26, 1954 INVENTOR. d Dav/s A7 7'0/E/YEYJ Dec. 11, 1956 G. J. DAVISALTITUDE SWITCH 2 Sheets-Sheet 2 Filed March 26, 1954 INVENTOR. Goodwind. Dav/s United States Patent ALTITUDE SWITCH Goodwin J. Davis, SanAntonio, Tex.

Application March 26, 1954, Serial No. 418,807

2 Claims. (Cl. 200-81) This invention relates to fluid distributionsystems, and more particularly to a system for controlling thedistribution of liquid to a tank or the like and for controlling thelevel of liquid in the tank.

The main object of the invention is to provide a novel and improvedfluid distribution system which involves simple components, which issubstantially self-regulating, and which is provided with means forsmoothing out line pressure disturbances or pulsations in the system.

A further object of the invention is to provide an improved liquiddistribution system for supplying liquid to an overhead tank, saidsystem involving inexpensive components, being reliable in operation,and being arranged to automatically provide liquid to the tank and tomaintain the liquid within predetermined limits of height in the tank.

A still further object of the invention is to provide an improved fluidpressure responsive switch device adapted to be employed in a fluiddistribution system for controlling an electric pump or otherelectrically operated device for furnishing fluid under pressure to thesystem, the switch being adjustable to operate at a predetermined fluidpressure in the conduit to which it is connected and being provided withmeans for delaying the operation thereof so that it will not respondimmediately, whereby pulsations or momentary disturbances of pressure inthe conduit will not cause operation of the electrical device associatedwith the switch.

A still further object of the invention is to provide an improved fluidpressure responsive switch adapted to be connected to a supply conduitleading to an overhead tank or the like, the switch being arranged to beoperated in response to changes in pressure in the conduit. such as whenthe level of liquid in the tank drops below a predetermined point, andbeing further arranged to be actuated reversely when the level of liquidin the tank rises above a predetermined point, whereby eflicient controlof the level of liquid in the tank will be obtained and whereby waste ofliquid by the overflowing of the tank will be prevented.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure 1 is a vertical cross sectional view taken through an improvedfluid pressure-responsive switch device constructed in accordance withthe present invention.

Figure 2 is an end elevational view of the control housing associatedwith the switch of Figure 1.

Figure 3 is an enlarged vertical cross sectional view taken on the line3-3 of Figure 1.

Figure 4 is an enlarged cross sectional detail view taken on the line 44of Figure 1.

Figure 5 is an elevational view showing a water distribu- I tion systemconstructed in accordance with the present invention and provided withfluid pressure-responsive switches as illustrated in Figures 1 to 4. 1

Figure dis a fragmentary elevational view showing the switch panel, mainpump, booster pump and a portion of the water supply conduit of thesystem illustrated in Figure 5.

Referring to the drawings, and more particularly to Figures 5 and 6, 11designates a water tank of the overhead type which is supplied withwater through a supply conduit 12 which connects to the vertical centralwater main 13 connected to the bottom of the tank 11. Water is suppliedto the conduit 12 from a well which is provided with an electric pump 14to the outlet of which the supply conduit 12 is connected, through amanual control valve 15, as shown in Figure 5. The conduit 12 ispreferably connected to the main pump 14 through a booster pump 16, asshown in Figure 6, the booster pump 16 being electrically operated by asuitable motor, as is the main pump 14.

The energizing circuit for the main pump 14 includes the cable 17containing the current supply conductors, said current supply conductorsbeing connected to a suitable source of electric power through a firstpressure-responsive control switch 18 whose contacts are arranged toclose responsive to a decrease in pressure below a predetermined valueof the liquid in the conduit 12. As shown, the pressure-responsiveswitch 18 is connected by a conduit 19 to the water supply conduit 12 sothat the pressure in the conduit 12 will be transmitted to thepressure-responsive switch 18, and will operate the switch in a mannerpresently to be described.

The conduit 19 may be connected at any desired point to the water supplyconduit 12, and may, if so desired, be connected to the water main 13 soas to cause the switch 18 to respond to changes in pressure in saidmain, whereby the pressure conditions resulting from changes in level ofthe liquid in the tank 11 will be more directly transmitted to theswitch 18. This alternative arrangement is indicated by the dotted linesshown at 19' in Figure 5, showing the alternative connection of theconduit leading to the pressure-responsive switch 18. As a furtheralternative, a similar pressure-responsive switch, shown at 18 in dottedview in Figure 5 may be mounted adjacent the tank 11 and may be providedwith a conduit 20' connected to the main 13 to transmit variations ofpressure in said main to the pressure-responsive switch 18'. It will beunderstood that the switch 18 may be connected in the electric currentsupply circuit for the electric pump 14 so as to control theenergization of the pump, and to energize the pump in response to adecrease in pressure below a predetermined value, indicating a decreasein liquid level in the tank 11 below a predetermined point in said tank.

As shown in Figure 6, the energizing circuit for the electric boosterpump 16 extends to the switch panel 21, said energizing circuitcomprising a cable 22 containing conductors which are connected to asource of electric power through a liquid pressure responsive switch 23generally smiliar to the switch 18 but arranged to close responsive toan increase in pressure above a predetermined value. It will beunderstood that the switch 23 as well as the switch 18 is normally open,and that the switch 18 closes in response to a decrease in pressurebeyond a predetermined value, whereas the switch 23 closes in responseto an increase in pressure beyond another predetermined value. Thus, theswitch 23 closes after the electric pump 14 has become energized and hasbecome primed, causing the liquid under pressure to flow to the boosterpump 16 and to produce an increase in pressure at its outlet conduit 25which is of a value above that required to close the switch 23. Theswitch 23 has its fluid pressure responsive means connected to theoutlet conduit 25 of the booster pump 16 by a conduit 26, whereby thepressure in the conduit 25 is transmitted to the switch 23, causing theswitch to close and to energize the boosterpump 16. This assures theprim 3 ing of the main pump 14 after said pump has become energized.

The liquid is pumped into the supply conduit 12 and flows therefrom tothe main l3, and into the overhead tank 11. After the liquid has reacheda predetermined level in the overhead tank 11, the liquid pressureresulting therefrom is transmitted to the switches 13 and 23, and whenemployed, to the switch 18'. As will be presently described, theseswitches are arranged to respond to predetermined upper pressure limitsto open the switches 18, 18 and 23, when the upper predetermined limitof pressure has been reached.

As shown in dotted view in Figure 6, the booster pump control switch. 23may be connected to the conduit 27 between the main pump 14 and thebooster pump 16, as by the conduit shown in dotted view at 26, insteadof to the outlet conduit of the booster pump, so that the switch 23 willrespond to the liquid pressure at the outlet of the main pump 14 insteadof the pressure of liquid forced through the booster pump 16.

Referring now to Figures 1 to 4, the fluid pressure responsive switch 18comprises a bottom chamber 34 having the top wall 31 to which isconnected the conduit 19 leading to the source of variable pressure, forexample, to the water supply conduit 12. The chamber contains a quantityof suitable fluid, such as mercury or the like. Any other suitableliquid or gas may be employed. The chamber 39 is formed with a dependingaxial reduced portion 32 containing the needle valve 33, said needlevalve having a threaded body 34 threadedly engaged in an axial threadedbore in the reduced portion 32 and having the stem 35 projecting througha gland 36 provided in the bottom end of the portion 32. Designated at37 is a second chamber of substantial height secured on the top wall 31of the first chamber, said second chamber having a bottom wall 33 towhich is connected a depending vertical tube 39 in the bottom end ofwhich the needle valve 33 is received. Secured in the bottom end of thetube 39 is the annular valve collar 49 which has a downwardly flaringbore cooperating with the upwardly tapering conical tip of the needlevalve 33 to define an annular restriction between the main chamber 30and the auxiliary upstanding chamber 37.

it will be understood that the mercury in the main chamber 30 will beforced upwardly into the chamber 37 by the pressure applied to the mainchamber from the conduit 19, and that the mercury in the auxiliarychamber 37 will rise to a level corresponding to the applied pressure.

The top Wall 31 of the main chamber 36 is provided with a suitable ventvalve 43 to allow air to be discharged from the main chamber 30.

The auxiliary chamber 37 is provided with the top wall 41 to which issecured the rectangular control housing 42. Centrally secured to the topwall 41 and in communication with the auxiliary chamber 37 is theexpansible bellows 44 which is arranged to change its volume in responseto the change in pressure applied to the main chamber 30 by the fluid inconduit 19, inasmuch as the mercury in the auxiliary chamber 37 willexert pressure on the air thereabove in chamber 37 and in the bellows 44and will expand said bellows in response to an increase in fluidpressure, as will be apparent from Figure 1.

Pivoted at 45 in the control housing 42 is a bell crank lever 46 havinga substantially horizontally extending lower arm 47 engaging the top endof the bellows 44 and having a'substantially vertically extending arm 48which is connected by a coiled spring 49 to the end of a screw 50. Thescrew 50 is threadedly engaged in a rotatable adjusting sleeve 51mounted in the vertical end wall 52 of the housing 42, the sleeve 51being provided with the external adjusting knob '53 having thereona-suitable scale which may be rotated with respect to a stationary indexmember 54 provided on the wall 52, the seale on the knob 53 beingcalibrated in terms of water levels in tank '11,

and the position of the scale with respect to the index member 54corresponding to the maximum water level desired in the tank. It will beunderstood that by rotating the member 51, the screw 50 is adjustedinwardly or outwardly, to increase or decrease the tension of the spring-559, and to thus increase or decrease the normal bias exerted by saidspring on the bell crank lever 46, and therefore to increase or decreasethe normal downward force exerted by the arm 57 on the top end of thebellows 44.

A U-shaped stop bracket 46 is secured to a side Wall of; housing 42having arms extending on opposite sides of tr e lever arm 48 to limitrotation of said lever arm, as shown in Figure 1.

Rigidly secured to the arm 47 of the bell crank lever 46 is thesubstantially horizontally extending arm 55 which is connected by a linkbar 56 to a disc member 5? on which is mounted the mercury switch 58.The disc member 57 is provided with the oppositely extending axial pivotpins 59, 59 which are rotatably received in pivot cups 60, 60 carried onthe pivot bracket 61 which is secured to the end wall 62 of the controlhousing 42. One arm of the pivot bracket 6i is provided with theparallel fingers 63, 63 which carry the opposing stop screws 64, 64disposed on opposite sides of a stop projection 65 secured on the disc57 to limit rotation of the disc between predetermined limits, namely,to limit rotation of the disc to a relatively small angle, of the orderof 30 or less.

When the disc 57 rotates clockwise past its intermediate position, asviewed in Figure l, the mercury switch 58 closes and remains closeduntil the disc 57 has been retated counterclockwise past itsintermediate position, as by the expansion of the bellows 44. The disc57 is yieldingly retained in its intermediate position by a springbiased detent element 65 which engages in a V-shaped notch 66 formed inthe periphery of the disc 57. The detent element 65 is secured to thelower end of a coiled spring 67 which is retained in a guide sleeve 63secured in a vertical position surrounding the spring 67 and having thetop bracket portion 69 secured to the top wall 70 of the switch housing42. Secured to the top end of the spring 67 is an abutment element 71which is engaged by the head 72 of a plunger 73 slidably supported in aguide sleeve 74 extending through the housing top wall 7% and beingintegrally formed on a bracket plate 75 secured to the bottom wall of anauxiliary housing 76 secured on the top wall 70 of the main controlhousing 42. The plate 75 is formed with a pair of upstanding lugs 77bctwen which is pivoted the lever 78 having the bottom arm '79 whichoverlies the top end of the plunger 73, as shown in Figure 3. Secured tothe top end of the arm 79 is an abutment pin 80.

Secured in the front wall 81 of the auxiliary housing 76 is a guidesleeve 82 in which is rotatably mounted a shaft 83 having secured to itsinner end a wedge-shaped disc member 84 and having secured to its outerend an adjusting knob 85. The wedge-shaped disc 84 has its inclinedsurface in engagement with the abutment pin 30, the pin being biasedinto engagement with the inclined surface of the wedge-shaped disc 84 bythe force of the spring 67, transmitted through plunger 73 to the bottomarm 79 of the lever 78. It will be readily apparent that by adjustingthe knob 85, the lever 78 may be rotated about its pivots 86 to adesired position, whereby the downward force exerted on the spring 67 bythe plunger 73 may be regulated within a reasonable range. This providesa means of varying the force exerted by the detent element 65 on thenotch 66, and hence provides a means of varying the amount of extraforce required to rotate the disc member 57 from its intermediateposition after the detent element 65 has entered the notch 66.

The front Wall 81 of the auxiliary housing 76 is provided with asuitable scale 88, calibrated in feet and inches, and the knob has apointer 89 which, when adjusted along the scale 88, provides a desiredlevel differential in the tank 11 between the level at which the switch53 closes and the upper level at which the mercury switch 58 is causedto open. The maximum height of liquid in the tank is of courseestablished by the adjustment of the control knob 53, which controls thetension of the spring 49.

The mercury switch 58 is connected by suitable wiring in the energizingcircuit of the electric pump, in the manner above explained, so as toenergize the pump when the liquid pressure drops below a predeterminedlevel, corresponding to a predetermined altitude of liquid in the tank11. A manually operated switch 91 is provided in the control housing 42which is connected across the mercury switch 58, and enables theoperator to manually close the energizing circuit for the electric pump,whenever desired. The switch 91 is normally open, namely, at times whenautomatic control of the tank level is desired.

It will be understood that operation of the switch devices 18 and 18' issubstantially the same, namely, when the fluid pressure drops below apredetermined value, determined by the setting of the limit control knob53 and the diiferential control knob 85, the decrease in pressure in theauxiliary chamber 37 allows the bellows 44 to contract and allows thespring 49 to rotate the bell crank lever 46 clockwise, as viewed inFigure 1. This rotation is transmitted by the link 56 to the disc member57, and when the force applied by the spring 49 is suflicient, the disc57 is rotated clockwise, as viewed in Figure 1 moving the disc away fromits normal intermediate position and causing the mercury switch 58 toclose. This energizes the pump 14, and, as will be presently explained,the booster pump 16, causing liquid to be pumped through the conduit 12to the main 13 and into the tank 11. As the level of liquid in the tank11 rises, the pressure transmitted through the conduit 19 to the lowerchamber 30 of the switch is increased, causing the mercury to moveupwardly in the auxiliary chamber 37, and thus causes the bellows 44 toexpand. When the liquid level in the tank has reached a heightsuflicient to overcome the combined effects of the springs 49 and 67,the disc member 57 is rotated counterclockwise past the intermediateposition of the disc, causing the mercury switch 58 to open, and causingthe electric pump to become deenergized. As the level of liquidsubsequently drops in the tank, the bellows 44 will contract, allowingthe disc 57 to rotate to a position wherein the detent element 65 entersthe notch 66, but as long as the liquid level remains above apredetermined low limit, the mercury switch 58 remains open. When thelevel of liquid in the tank drops below said low limit, the mercuryswitch 58 closes, by the process above described.

The needle valve 33 is adjusted to provide an annular restrictionbetween the main chamber 30 and the auxiliary chamber 37, whereby theflow of mercury from the main chamber 30 to the auxiliary chamber 37 andreturn flow of said liquid is retarded, thus preventing response of thesystem to momentary pulsations of pressure or other short term pressuredisturbances. The degree of retardation may be regulated by adjustingthe needle valve 33 to provide a desired restriction between thechambers 30 and 37.

The booster control switch 23 is similar in construction to the controlswitch 18 except that it is arranged to close on an increase in fluidpressure in the conduit 25 or conduit 27, above a predetermined valueand to open when said pressure drops below a lower predetermined value.Thus, the booster pump 16 will remain in operation from the time thatthe main pump 14 becomes primed until the main pump 14 is deenergized bythe opening of its control switch 18. As shown in Figure 6, a checkvalve 16' is employed between the conduit 12 and its control valve 15and the outlet conduit of the booster pump 16 to prevent the switch 23from being affected by changes in pressure in the conduit 12.

While a specific embodiment of an improved fluid distribution system andfiuid pressure responsive switch means forming a part thereof have beendisclosed in the foregoing description, it will be understood thatvarious modifications within the spirit of the invention may occur tothose skilled in the art. Therefore, it is intended that no limitationsbe placed on the invention except as defined by the scope of theappended claims.

What is claimed is:

1. In a fluid pressure-responsive switch, a first chamber adapted to beconnected to a fluid conduit subject to changes in pressure, a secondchamber, conduit means extending through the first chamber andconnecting said chambers, a restriction in said conduit means to providea time delay between a change in fluid pressure in the first chamber anda corresponding change in pressure in the second chamber, an expansibleflexible chamber connected to and communicating with said secondchamber, a pair of contacts, and means engaging said expansible chamberand being formed and arranged to open and close said contacts inresponse to changes in volume of said expansible flexible chamber, saidlast-named means comprising a support mounted on said second chamber, arotary member mounted on said support, a mercury switch secured to saidrotary member, adjustable detent means frictionally engaging said rotarymember, a lever pivoted to said support and engaging said expansibleflexible chamber, link means connecting said lever to said rotarymember, and adjustable spring means biasing said lever toward engagementwith said flexible chamber, whereby the force required to rotate saidrotary member may be adjusted.

2. In a fluid pressure-responsive switch, a first chamber adapted to beconnected to a fluid conduit subject to changes in pressure, a secondchamber, conduit means extending through the first chamber andconnecting said chambers, a restriction in said conduit means to providea time delay between a change in fluid pressure in the first chamber anda corresponding change in pressure in the second chamber, an expansibleflexible member connected to and communicating with said second chamber,a pair of contacts, and means engaging said expansible chamber and beingformed and arranged to open and close said contacts in response tochanges in volume of said expansible flexible chamber, said last-namedmeans comprising a support mounted on said second chamber, a rotarymember having an arcuate periphery provided with a detent notch, saidrotary member being rotatably mounted on said support, a mercury switchsecured to said rotary member, an adjustable spring detent mounted onsaid support and yieldably engaging in said notch, a lever pivoted tosaid support and engaging said expansible flexible chamber, link meansconnecting said lever to said rotary member, a spring connecting saidlever to said support and opposing the expansion of said expansiblechamber, and means adjusting the tension of said spring, whereby theforce required to rotate said rotary member may be adjusted.

References Cited in the file of this patent UNITED STATES PATENTS1,293,547 Reese Feb. 4, 1919 1,461,470 Ackley July 10, 1923 1,734,233Shannon et a1. Nov. 5, 1929 1,762,219 Faber June 10, 1930 1,980,095Rowley Nov. 6, 1934 2,043,579 Edrington et a1. June 9, 1936 2,274,558Murray Feb. 24, 1942 2,440,981 Smith May 4, 1948 FOREIGN PATENTS 353,225Great Britain July 23, 1931 528,580 Great Britain Nov. 1, 1940 931,059France Sept. 15, 1947

